Process for improving the wet fastness properties of dyeings on polyamide fibre material

ABSTRACT

A process for improving the wet fastness properties of dyeings on synthetic polyamide fiber material is provided. The process is characterized in that preparations are applied to the fiber material at temperatures of 20* to 120*C, which contain a watersoluble fixing agent with affinity for the fiber, an organic solvent or solvent mixture and at most 10 percent of water, relative to the preparation, and also, optionally an organosoluble dispersing agent. The fiber material thus treated shows very good fastness properties and no deterioration of handle.

United States Patent [1 1 Mueller et al.

[ Oct. 16, 1973 PROCESS FOR IMPROVING THE WET FASTNESS PROPERTIES OF DYEINGS ON POLYAMIDE FIBRE MATERIAL [75] Inventors: Volkmar Mueller, Arlesheim; Hans Ulrich Berendt, Allschwil; Melvin Harris, Dornach, all of Switzerland [30] Foreign Application Priority Data Sept. 3, 1970 Switzerland 13145/70 [52] US. Cl 8/165, 8/94, 8/173, 8/174 [51] Int. Cl D06p 5/04 [58] Field of Search 8/165, 173, 174, 8/65, 94

[56] References Cited UNITED STATES PATENTS 3,524,718 811970 Nador et a1 8/170 3,663,157 5/1972 Gilgien et al. 8/173 R27,386 6/1972 Soiron et a1, 8/165 3,118,723 l/l964 Harding 8/14 Primary ExaminerLeon D. Rosdol Assistant Examiner-T. 1. Herbert, Jr. Attorney-Harry Goldsmith et al.

[57] ABSTRACT A process for improving the wet fastness properties of dyeings on synthetic polyamide fiber material is provided. The process is characterized in that preparations are applied to the fiber material at temperatures of 20 to 120C, which contain a water-soluble 'fixing agent with affinity for the fiber, an organic solvent or solvent mixture and at most 10 percent of water, relative to the preparation, and also, optionally an organosoluble dispersing agent. The fiber material thus treated shows very good fastness properties and no deterioration of handle.

10 Claims, No Drawings PROCESS FOR IMPROVING THE WET FASTNESS PROPERTIES OF DYEINGS ON POLYAMIDE FIBRE MATERIAL It is already known that apart from the customary aqueous dyeing liquors for dyeing textile material, liquors can also be used which contain an organic solvent as the liquor medium. This dyeing from organic solvents has the advantage, for example, that the amount of efi'luent which arises on dyeing can be kept low. it has been found, for dyeings from aqueous liquors and from organic liquors, that the fastness properties, for example the wet fastness properties, of dyeings on polyamide fibre material, especially on synthetic polyamide fibre material, do not always meet requirements. As a result of the present invention, these disadvantages are avoided or at least restricted to an acceptable extent. I

The present invention therefore relates to a process for improving the wet fastness properties of dyeings on synthetic polyamide fibre material. The process is characterised in that preparations are applied to the fibre material, at temperatures of 20 to 120C, which contain a water-soluble fixing agent with affinity for the fibre, an organic solvent or solvent mixture and at most l percent of water, relative to the preparation, and also, optionally, an organo-soluble dispersing agent.

These preparations are, for example, manufactured by working the fixing agent into a paste with'the dispersing agent and subsequently diluting this paste with an organic solvent to the desired volume, and before or after the addition of the organic solvent water can optionally also be added. However, it has proved very suitable to dissolve the fixing agent in a little water and then to dilute this solution appropriately by adding a solution of the dispersing agent in the organic solvent. Dispersions of fixing agent in organic solvents, which are stable and do not demix, are thus obtained. Instead of water, a hydrophilic solvent which is easily miscible with water can also be used, and the liquor canthen also be made up to the desired volume with this solvent. The addition of a dispersing agent then becomes optional. 1

Suitable solvents for the process according to the in vention are, for example, solvents which are immiscibleor of only restricted miscibility with water, such as the petrol hydrocarbons, for example petroleum ether, benzene and halogenated benzenes or benzenes substituted with low molecular alkyl groups, such as, for example, toluene, xylene, ethylbenzene, cumene, monochlorobenzene and dichlorobenzene; alicycliccompounds, such as, for example, tetralin and cyclohexane,

ether and diethylene glycol monomethyl ether or monoethyl ether, and also pyridine, acetonitrile, diacetone-alcohol, ethylene carbonate, 'y-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, N- methylpyrrolidone, tetramethylurea, tetramethylenesulphone, dimethylsulphoxide and others. Mixtures of the solvents mentioned can also be used.

The fixing agents possessing fibre affinity which are applied, in order to improve the wet fastness properties, to the fibre material after the actual dyeing process, but canalso be present in the dyebath and are then absorbed simultaneously with the dyestuff onto the substrate, are as a rule anionic water-soluble compounds. They should not possess an intrinsic colour and should at least not change the intrinsic colour of the fibre material which is to be treated.

Particularly suitable fixing agents are the watersoluble anionic polycondensation products of diarylsulphones possessing at least one phenolic hydroxyl group with formaldehyde. Possible aromatic components are bicyclic, but above all mono-cyclic, compounds which possess at least one phenolic hydroxyl group. In addior cyclohexanol, but preferably halogenated hydrocarbons, such as, for example, the solvents trichloroethylene and perchloroethylene which are used in the drycleaning industry, and also chloroform, methylene chloride, carbon tetrachloride, dibromoethylene and the chlorinated ethanes, such as l,l-dichloroethane, l,2-dichloroethane, l,l,l-trichloroethane and l,l,2,2- tetrachloroethane. A further group consists of the solvents which are miscible with water, such as, for example, the aliphatic alcohols methanol, ethanol or the propanols; ketones, such as acetone, methyl ethyl ketone and cyclohexanone; ethers and acetals, such as diisopropyl ether, diphenylene oxide, dioxane and tetrahydrofurane; glycol derivatives, such as ethylene glycol monomethyl ether, monoethyl ether and monobutyl tion to the hydroxyl group, however, other substituents can also be present, such as sulphonic acid groups, halogen atoms or alkyl radicals, especially alkyl radicals with one to four carbon atoms. The compounds of the type of phenol, the monoalkylphenols or dialkylphenols, for example the cresols or xylenols, the monohalogenophenols or dihalogenophenols, for example the chlorophenols or dichlorophenols, resorcinol or pyrocatechol, may be mentioned.

The sulphones are manufactured from the phenolic compounds described above in accordance with methods which are in themselves known, for example by reaction with sulphuric acid at elevated temperature. In

this reaction it is also possible to use mixtures of the aromatic components described.

These sulphones are subjected to polycondensation with formaldehyde, following methods which are in themselves known, for example in an acid or alkaline medium at elevated temperature. The condensation need, however, not be carried out exclusively with sulphones but can also take place with mixtures of sulphones and sulphonic acids of the phenolic compounds described. If such is the case, the polycondensation product should contain at least 30, and preferably 40, mol per cent of sulphone. If, on the other hand, exclusively sulphones are subjected to poly-condensation, either the sulphones are sulphonated before the condensation, or the polycondensates are sulphonated. It is also possible to introduce sulphonic acid groups either before or after the condensation with formaldehyde. Condensation products of aromatic sulphonic acids, which are free of hydroxyl groups, with formaldehyde are also suitable. Additionally there may still be mentioned those condensation products which instead of the SO, grouping in the diarylsulphones described above, contain a sulphur atom (diarylsulphide type), an oxygen atom (diphenyl-ether type), a methylene (CH,) grouping or substituted methylene grouping or a keto group As dispersing agents for the manufacture of the dispersed fixing agent preparations,anionic or non-ionic and it is necessary to ensure that these are of good solubility in the organic solvents employed. The solubility of the dispersing agents should not be less than 0.5 g/l.

Suitable representatives of such surface-active compounds belong to the following types of compounds:

a. Ethers of polyhydroxy compounds, such as polyoxyalkylated fatty alcohols, polyoxallrylated polyols, polyoxalkylated mercaptans and aliphatic amines, polyalkylated allcylphenols and alkylnaphthols, polyoxalkylated allrylarylmercaptans and alkylarylamines; and also the corresponding esters of these compounds with polybasic acids, such as sulphuric acid or phosphoric acid, optionally also in the form of ammonium salts or amine salts.

b. Fatty acid esters of ethylene glycol and polyethylene glycol as well as propylene glycol and butylene glycol, of glycerol or of polyglycerols and of pentaerythritol, as well as of sugar alcohols, such as sorbitol.

c. N-Hydroxyalkyl-carbonamides, polyoxalkylated carbonamides and sulphonamides.

As advantageously usable dispersing agents from these groups there may, for example, be mentioned: the monoethanol-amine salt of the phosphoric acid ester of the addition product of oleyl alcohol and six mols of ethylene oxide; the ammonium salt of the acid sulphuric acid ester of the addition product of 17 mols of ethylene oxide to oleyl alcohol; the addition product of four mols of ethylene oxide to nonylphenol; the addition product of eight mols of ethylene oxide to one mol of p-tert.-octylphenol; the addition product of 9 mols of ethylene oxide to nonylphenol; the addition product of 8 mols of ethylene oxide to cetyl alcohol or oleyl a1- cohol; the addition product of coconut fatty acid and 2 mols of diethanolamine; the addition product of or 6 mols of ethylene oxide to castor oil, the addition product of mols of ethylene oxide to the alcohol C H Ol-l, ethylene oxide addition products to di-{aphenylethyl}-phenols, polyethylene oxide tertwdodecyl thioether, polyamine-polyglycol ethers, the addition product of 15 or 30 mols of ethylene oxide to 1 mol of amine C, H, NH, or C l-l ,Nl-l the ester of oleic acid Mixtures of the surface-active compounds mentioned are also suitable.

The simultaneous application of the fixing agents with the dyestuff, that is to say their application in a dye-bath, takes place from organic solvent liquors by the exhaustion process. The improvement in the wet fastness properties in this case relates only to dyeings from organic solvents. If this is followed by an aftertreatment with the fixing agent, the dyeings can have been produced either in liquors of organic solvents or in aqueous baths. When using organic solvent liquors the after-treatment can be carried out in the exhausted dyeing liquor or in a new liquor. When using aqueous liquors it is advisable to effect an intermediate drying of the fibres. The finishing with the fixing agent is always carried out from an organic solvent.

The temperature ranges for the application are between 20 and 120C, preferably between 40 and C. The treatment times are approximately between one and 30 minutes, preferably between five and 15 minutes, in the case of the after-treatment, whilst this time corresponds to the dyeing time if the fixing agent is applied from the dyebath.

The pl-l values of the preparations can lie in the acid, neutral or alkaline range and approximately encompass a range of pH 4 to 9, preferably of pl-l 5 to 8. The pH value is adjusted by, for example, low molecular organic acids, such as formic acid, acetic acid or monochloroacetic acid, or ammonia.

The amounts in which the fixing agent is used vary within wide limits and are 0.1 to 10 percent, relative to the impregnating liquor, in the case of the padding process, or 0.1 to 10 percent, preferably 0.5 to 5 percent, relative to the fibre material, if the exhaustion process is used.

The particular amount of dispersing agent required varies correspondingly, and preferably both components are proportional to one another, that is to say the amount of dispersing agent also increases with increasing amount of fixing agent. The ratio of fixing agent to dispersing agent is appropriately between 1:100 and 1:2. Suitable liquor ratios are between 1:5 and 1:100, preferably between 1:20 and 1:50.

Fibre materials which are suitable according to the invention are mainly synthetic polyamide fibres, such as nylon .6, nylon 6,6, nylon 6,10 (from hexamethylenediamine and sebacic acid), nylon 11 or nylon 6,6/6 (copolymers of hexarnethylenediamine, adipic acid and s-caprolactam), and also mixed fabrics containing synthetic polyamide fibres. The fibre material can be in any desired states of processing.

The fibre material is dyed in a homogeneous solubilised preparation or dispersion of the dyestuff in an organic solvent or solvent mixture. The acid dyestuffs,

dispersion dyestuffs, reactive dyestuffs and metal complex dyestuffs which are suitable for dyeing the synthetic polyarnide fibres belong, for example, to the known classes of the monoazo and disazo dyestuffs as well as of the anthraquinone, methine, azomethine, azostyryl and formazane dyestuffs. These dyestuffs, which are water-soluble or only dispersible in water, can be used individually or as mixtures. If desired, other suitable types of dyestuffs can also be used.

The polyamide fibre material is thus appropriately dyed according to the known exhaustion process. For the one-bath application of dyestuff and fixing agent, the dye-stuffs can, for example, appropriately be prepared as follows: working the dyestufi into a paste with the dispersing agent, diluting with the desired amount of an organic solvent, and mixing this preparation with a preparation of the fixing agent which has been diluted with water or with an organic solvent. A different sequence is also possible.

For finishing the fibre substrates which have been treated in a single bath, or been after-treated, it is desirable largely to centrifuge off the liquor and then to dry the substrate in a stream of warm air. The fibre substrates treated according to the invention show good to very good fastness properties and no deterioration of handle as compared to untreated material.

1n the examples which follow, unless otherwise stated, the parts denote parts by weight and the percentages denote percentages by weight.

4. Condensation product of 4,4'-dihydroxydiphenylsulphone, naphthalene, sulphuric acid and formaldehyde.

5. Manufacture of the fixing agent: 35 g of concen- EXAMPLE 1 5 trated sulphuric acid are added dropwise at room temperature to a suspension of 70 g of 4,4- A nylon Helanca tricot is prewetted for minutes dihydroxy-3,3'-dimethyl-diphenyl-sulphone in 35 g at 40C, using a liquor ratio of 1:40, in an aqu iiof acetic anhydride, whilst stirring. Thereafter the quor which contains 1.5 percent of the sodium salt of temperature is raised to 98 100C and kept at dodecylbenzene-sulphonic acid, 1.5 percent of the ad- 10 s le el or SiX hours- 75 ml of Water are now duct of 1 mol of fatty amine and 30 mols of ethylene a ded in P rtions at a pressure of 30 to 50 mm Hg oxide and 1.5 percent of acetic acid (80 percent eolumn- At the Same me 38 m1 of liquid are disstrength). Thereafter 2.3 percent of th d st ff C,I tilled from the reaction mixture. The remaining re- Acid Red 57 and 1.6 percent of the dyestuff C I. A id action mixture is diluted with a further 20 ml of wa- Blue 72 are added, the dyebath is heated to the boil ter, treated with g of 30 percent strength aqueover the course of 30 minutes, dyeing is carried out for 0H5 formaldehyde Solution and heated five one hour at this temperature, and the dyeing is then fmou to 05C It iS en allo ed o Cool ished by rinsing and drying. A violet dyeing is obtained. and 30 Percent reng h Sodium hy r xi e Solution After-treatment is added to the viscous condensation product until 1 g of one of the fixing agents 1 t 4 d s ib d b l 20 a pH value of 7 is reached. The resulting product is taken up in 15 ml of water. 10 g of the adduct of noncan be diluted with Water as e i e ylphenol and six mols of ethylene oxide, dissolved in 6. A Product with similar Properties is Obtained 985 ml of perchloroethylene, are then added to this o e e ddition Of formaldehyde, the reaction aqueous solution, whilst stirring. 50 g of the nylon mixture is adjusted to 3 P value of 8 to with Helanca tricot dyed as above are treated in this liquor percent strength sodium hydroxide solution. for five or 15 minutes at 50 or 70C with or without the 7- A mixture of 3 g o 4,4-dihydroxy-3-methyladdition of acid (monochloroacetic acid, up to a pH diphenylsulphone and 150.5 g of l-hydroxy-Z- value of about 4). methylbenzene-4-sulphonic acid in 100 ml of water Fixing Agents is rendered alkaline with 463 g of 30 percent 1. Manufacture of the fixing agent: g of concen- 30 strength aqueous sodium hydroxide solution. After trated sulphuric acid are added dropwise at room addition of 162 g of 37 percent strength aqueous temperature to a suspension of 70 g of 4,4'- formaldehyde solution, the reaction mixture is dihydroxydiphenylsulphone in 35 g of a ti anhystirred at 100 to 102C for five to six hours. The dride, whilst stirring. Thereafter the temperature is esulting C nd nsation product 7 Can be diluted raised to 98 100C and kept at this level for six 35 with water as desired without resulting in precipitahours. 75 ml of water are now added in portions at tion.

a pressure of 30 to 50 mm Hg column. At the same Table l which follows summarises the values of the time, 88 ml of liquid are distilled from the reation e ne properties Ob a ned through the aftermixture. The remainder of the reaction mixture is treatment of the dyeing with the fixing agents mendiluted with a further 20 m1 of water, treated with 40 tioned- 20 g of 30 percent strength aqueous formaldehyde The tests were carried out in accordance with SNV solution and heated to 100 105C for five hours. Standard Specifications 195,819, 195,813 and The whole is then allowed to cool and 30 percent 195,324-

strength sodium hydroxide solution is added to the SNV 195,813: The finished fabric is treated at 60C viscous condensation product until a pH value of 7 with a solution containing 2 g of Sodium Car is reached. The resulting product can be diluted hy r )ll and 5 g of soap/l 30 minutes, liquor ratio with water as desired. 1:50.

2. Condensation product of a sulphone mixture (4,4'- SNV 195,819: The finished fabric is wetted in water dihydroxy-dipheny1su1phone and 4,2 -dihydroxybetween 2 undyed fabrics. After pouring off the excess diphenylsulphone), phenolsulphonic acid and water, the test specimen is subjected to a certain load formaldehyde. in a suitable apparatus. Time; four hours,temperature 3. Condensation product of a sulphone mixture (4,4'- 37C. The test specimen is then separated from the surdihydroxy-diphenylsulphone and 4,2 '-dihydroxyface-dyed accompanying fabric and the fabrics are sepdiphenylsulphone), sulphuric acid and formaldearately dried. The colour change and the bleeding are hyde. assessed.

TABLE I Fastness tests SNV 195,819 SNV 195,813 SNV 195,824

On after-treatment with product Addition Application conditions of acid 1 2 3 4 1 2 3 4 1 2 3 4 Untreated 5 minutes, 50 C o 15 minutes, 50 C. Do

5 minutes, C

o. 15 minutes, 70 C Do SNV 195,824: Fastness to perspiration (alkaline): the finished fabric is treated between undyed accompanying fabrics for 30 minutes at room temperature in a liquor which contains sodium chloride, disodium phosphate and histidine monohydrochloride monohydrate. pH value: 8.0 (adjusted with sodium hydroxide). Liquor ratio 1:50. Thereafter the excess liquor is removed. The test specimens are kept for four hours at 37C and then dried without rinsing. The change in the III dyeing, and the bleeding, are assessed. l

TABLE 11] The assessment is made with ratings 1 to 5, being the best rating. Application Addition Fastness Tests conditions of d SNV SNSV 3 SNV aci 195.819 19 .31 195,824 EXAMPLE 2 untreatedo 2 3-4 2 A nylon Helanca tricot is dyed in accordance with g if, 2' Z 2 Example 1 with l.2 percent of the dyestufi' of the for- 15 mins. y 4 mula 15 mins., 50C no 4-5 4 4-5 5 mins., 70C yes 4 4 4 5 mins., 70C no 4 4 4 15 mins., 70C yes 4-5 4-5 4-5 0 v NH G 15 mins., 70C no 44 4-s 4-5 EXAMPLE 4 9 7 v A nylon-6,6 woven tricot is dyed in accordance with Example .3 and after-treated for 15 minutes at 70C. The nature of the fixing agent and the amount employed can be seen from Table IV. The fastness tests were carried out without fixing the dyed and finished and 1.5 percent of the dyestuff of the formula 0 NH A 2 fibre material, and also after fixing seconds at 210C)... SO33 TABLE IV Fastness tests Y SNV 195,319 SNV 195,813 sNv195,s24

NH-C 0-014 0 NH Q 3 Nature and amount of Not Not; Not

. the fixing agent fixed Fixed fixed Fixed fixed Fixed Untreated 2-3 3 2-3 2%,1... 5 5 4-5 5 4-5 5 and is also after-treated as described. Table 11 contains i 2 2:: g g the values of the wet fastness properties of the dyeing 5 1:; g achieved by the treatment with the fixing agent. ZZ t? '2 1:? g H 2%, 4-5 4-5 4-5 5 4-5 5 4o 4%, 4 4-5 4-5 4-5 5 TABLE 11 i '7 I V Fastness tests SNV 195,819 SNV 195,813 SNV 195,824

0n after-treatment with product Addition Application conditions 0: acid 1 2 3 4 1 2 3 4 l 2 3 4 Untreated 3 3 3 5 minutes, 50 c 4-5 5 4-5 3 3 .3 3 5 4-5 4-5 4 D 4-5 5 4 3 a 3 3 4-5 4 4 4-5 15 minutes, 50 c 5 5 4-5 a 3 3-4 3 5 4-5 4-5 4-5 0 4-5 5 4-5 3, 3 3 3 5 5 4 4 5 minutes, 70 C- 5 5 4-5 3-4 3-4 3-4 3-4 5 5 4-5 4-5 1 4-5 5 4-5 3-4 3-4 3-4 3-4 5 5 4-5 4 15 minutes, 10 c 4-5 5 4-5 3-4 3-4 3-4 3-4 5 4-5 4-5 4 Do---.. 5 5 4-5 3-4 3-4 3-4 3-4 5 4-5 4-5 4-5 EXAMPLE 3 EXAMPLE 5 40 g of nylon-6,6 woven tricot are dyed, using a 1iquor ratio of 1:25, in a perchloroethylene liquor which contains 1.32 g of a dyestuff of the formula 1 l I SOaI-I The system is heated from 30C to 165 C over the course of 30 minutes and is kept at this temperature for 1 g of the fixing agent 2 are mixed with 25 ml of water. 1.65 g of the dyestuff of the forrnula NH: NH;

blue Y r m-4434: O-GHCI are worked into a paste with 10 g of the addition product of 7 l5 molsof ethylene gxide tg oleylamine and made up to 975 ml with perchloroethylene and filtered. This dyestuff liquor is then added to the aqueous solution of the fixing agent, whilst stirring.

50 g of a nylon 6,6 fabric are treated for 60 minutes with this liquor, the system being heated from 40C to 100C over the course of 30 minutes and the fabric being dyed and finished for a further 30 minutes at this temperature. 2 percent of fixing agent, relative to the fibre material, are employed; the liquor ratio is 1:20 and the pH value is 5.6.

A significant improvement in the wet fastness properties is achieved. The depth of colour obtained corresponds to that obtained in a comparison dyeing without fixing agent, but otherwise under the same conditions.

The following preparations are produced in accordance with Example 5, and applied with equally good results: 7

a. 2 g of fixing agent l/50 ml of water 4.4 g of the dyestuff C.l. Acid Blue 106 20 g of the addition product of 8 mols of ethylene oxide to p-tert. octylphenol solvent: trichloroethylene substrate: 200 g of nylon 6 woven tricot liquor ratio: 1:5 2 percent of fixing agent/fibre material pH value: 5.3

b. 0.2 g of fixing agent 3/10 ml of water 0.33 g of the abovementioned dyestuff 5 g of the addition product of 8 mols of ethylene oxide to oleylamine solvent: perchloroethylene substrate: 10 g of nylon 6,6 fabric liquor ratio: 1:100 2 percent of fixing agent/fibre material pH value: 5.7

c. 0.8 g of fixing agent 4/20 ml of water 1.76 g of the abovementioned dyestuff 10 g of the reaction product of coconut fatty acid and 2 mols of diethanolamine solvent: perchloroethylene substrate: 80 g of nylon 6,6 l-lelanca tricot liquor ratio: 1212.5 1 percent of fixing agent/fibre material pH value: 5.4

EXAMPLE 6 g of nylon 6,6 woven tricot are dyed for one hour at 100C, using a liquor ratio of 1:50, in a perchloroethylene liquor which contains 0.66 g of the dyestuff of the formula orange HNCOCHCH2 Br Br thereafter the solvent is centrifuged off and the fabric is dried with warm air. The amount of fixing agent applied to the fibre material is 5 percent at a liquor ratio of 1:50. A good improvement in the wet fastness properties of the fibre material dyed and finished in this way is achieved.

The following preparation can also be used for the after-treatment, with equally good results:

1 g of fixing agent 7, worked into a paste with 5 g of the above addition product and made up to 1000 ml with toluene.

EXAMPLE 7 a. A nylon-6,6 Helanca tricot is dyed in a perchloroethylene liquor which contains 1.825 g of the dyestuff of the formula blue 10 g/l of the addition product of 9 mols of ethylene oxide to nonylphenol and 15 ml/l of water. The liquor ratio is 1:40.

The fabric is introduced into the liquor at 40C, the system is heated to C over the course of 30 minutes, and dyeing takes place for 30 minutes at this temperature. The dyeing takes place for 30 minutes at this temperature. The dyeing is finished by centrifuging off the solvent and drying with warm air.

b. Dyeing as a), but without addition of water to the dyebath;

c. Dyeing as a), and after-treated; 15 minutes at 70C with a liquor (liquor ratio 1:20, pH value 5.6) containing: 2 percent of fixing agent 2, 15 m1/] of water, 5 g/l of the above addition product.

d. Dyeing b), after-treated as c). 1

e. Dyeing liquor as a), but at the same time containing 2 percent of fixing agent 2, relative to the fibre weight. w

Equally good results are obtained with fixing agent 6.

Table 5 contains the fastness properties of the dyeings (a) to (e).

TABLE V Fastness Tests Dyeing SNV 195,819 SNV 196,824

a 2-3 3 b l-2 1-2 0 4-5 5 d 4-5 5 2 4-5 5 It can be shown unmistakably that a simultaneous treatment or an after-treatment with a fixing agent results in significant improvements in wet fastness properties.

Equal results are achieved with dyeings which have been obtained with the acid dyestuff C.l. Acid Blue 106 instead of the reactive dyestuff mentioned above.

1. Process for improving the wet fastness properties of dyeings on synthetic polyamide fibres, which comprises applying to the fibres at temperature of 20 to C a) simultaneously with the dyestuffs in organic solvent, or b) as after-treating of dyeings produced in organic solvent or aqueous liquors, a preparation which contains as fixing agents water-soluble anionic polycondensation products of arylsulphonic acids and/or diarylsulphones with formaldehyde, an organic solvent or solvent mixture and at most percent of water, relative to the preparation.

2. Process according to claim 1, wherein the fixing agents are condensation products of diarylsulphones, possessing at least one phenolic hydroxyl group, with formaldehyde.

3. Process according to claim 1, wherein the fixing agents are diarylsulphones which are derived from monocyclic hydroxy aryl compounds.

4. Process according to claim 1, wherein the fixing agents are condensation products of dihydroxydiphenylsulphones with formaldehyde.

5. Process according to claim 1, wherein the fixing agents are condensation products of sulphonic acids of dihydroxy-diphenylsulphones with formaldehyde.

6. Process according to claim 1, wherein the organic solvents are l,l,l-trichloroethane, trichloroethylene and/or perchloroethylene.

7. Process according to claim 1, wherein the preparation additionally contains an organo-soluble dispersing agent.

8. Process according to claim 7, wherein the dispersing agents aresurface-active, organo-soluble non-ionic or anionic compounds, which in particular are obtained by addition of ethylene oxide to long-chain amines, alcohols, phenols or fatty acid esters.

9. Process according to claim 1, wherein the amounts of fixing agent are 0.1 to l0 percent relative to the fibres.

10. A stable fixing agent preparation for carying out the process according to claim 1, which contains as fixing agent water-soluble, anionic polycondensation products of arylsulphonic acids, and/or diarylsulphones with formaldehyde and an organic solvent or solvent mixture and at most 10 percent of water, relative to the total preparation. 

2. Process according to claim 1, wherein the fixing agents are condensation products of diarylsulphones, possessing at least one phenolic hydroxyl group, with formaldehyde.
 3. Process according to claim 1, wherein the fixing agents are diarylsulphones which are derived from monocyclic hydroxy aryl compounds.
 4. Process according to claim 1, wherein the fixing agents are condensation products of dihydroxy-diphenylsulphones with formaldehyde.
 5. Process according to claim 1, wherein the fixing agents are condensation products of sulphonic acids of dihydroxy-diphenylsulphones with formaldehyde.
 6. Process according to claim 1, wherein the organic solvents are 1,1,1-trichloroethane, trichloroethylene and/or perchloroethylene.
 7. Process according to claim 1, wherein the preparation additionally contains an organo-soluble dispersing agent.
 8. Process according to claim 7, wherein the dispersing agents are surface-active, organo-soluble non-ionic or anionic compounds, which in particular are obtained by addition of ethylene oxide to long-chain amines, alcohols, phenols or fatty acid esters.
 9. Process according to claim 1, wherein the amounts of fixing agent are 0.1 to 10 percent relative to the fibres.
 10. A stable fixing agent preparation for carrying out the process according to claim 1, which contains as fixing agent water-soluble, anionic polycondensation products of arylsulphonic acids, and/or diarylsulphones with formaldehyde and an organic solvent or solvent mixture and at most 10 percent of water, relative to the total preparation. 